Maybe I'm missing something or perhaps it's related to the fact that I'm doing it on Safari, but the Tampermonkey console shows a parsing error: invalid token on the last line of the script. I just did a copy and paste of the last update from EvilHero.

Again, maybe I'm doing something wrong or maybe it's safari, but I'm just getting more errors in Tampermonkey... I'm using V.4.7.5826 if that matters... When I go to CV, I also don't see any mylar button on a comic page. Here's what I'm getting:

Line 9 warning shows $ is not defined, twice
Line 10 shows an error "Implicit global variable, assign as global property instead" and the warnings for current and $ not defined.
Line 11 shows the same $ warnings from line 9

I"m limited in my troubleshooting abit on this, as I can only test on Chrome/IE.

However, the errors you listed are fine - mine has the same thing in them (due to $ being the declaration of a variable I believe), and it still works. The Mylar logo will only appear beside the series title when you're viewing the series page, not an issue page. (ie. https://comicvine.gamespot.com/volume/4050-22775/). Make sure you have the script enabled within the Tampermonkey dashboard. I'm using version 4.6 (having problems updating to 4.7 for some reason, but I don't think it would break things)

I've read about some problems with Tampermonkey and using Safari due to apple pulling back some support of some aspects that are required for Tampermonkey to work - but I honestly haven't a clue in regards to what's working vs. what's not when it comes to Mac stuff.

ok, I see the button on the series... clicking it brings up a new, blank tab with my server name in the address... it seems like it works, and I can now see the series in mylar... I assume that's all it needs to do, so I think we're good to go... done in Safari, btw, so I guess it works there (for now)